1. Field of the Invention
The present invention relates to systems and methods for lifting a residential house or other building and placing it onto an elevated foundation. More specifically, the present invention relates to the pile cap connectors used to secure the deep pile foundation to a lifted a residential house or other building.
2. The Relevant Technology
Revised FEMA (Federal Emergency Management Agency)/NFIP (National Flood Plan Insurance Program) requirements (2012-2013; pending finalization in 2014) will require hundreds of thousands of residential houses, in United States coastal flood hazard zones, to be lifted and placed onto elevated foundations in order to qualify for NFIP coverage. Presently, the conventional industry standard process for lifting a residential house and placing it onto an elevated concrete block or a helical micropile foundation, with a two-to-six foot deep concrete grade berm, has a cycle time of approximately 28 days.
Coastal construction requirements are different from inland construction. Flood levels, velocities, and wave action in coastal areas tend to make coastal flooding more damaging than inland flooding. Further, coastal erosion may undermine buildings and destroy land, roads, utilities, and infrastructure. Wind speeds are typically higher in coastal areas and require stronger engineered building connections and more closely spaced nailing of building sheathing, siding, and roof shingles. Wind-driven rain, corrosion, and decay are also frequent concerns in coastal areas.
In general, homes in coastal areas must be designed and built to withstand higher loads and more extreme conditions. Homes in coastal areas also require more maintenance and upkeep. Coastal buildings must be designed to withstand coastal forces and conditions. Coastal buildings must be built as designed and sited so that erosion does not undermine the building or render it uninhabitable. A well-built but poorly sited building may be undermined. Even if a building is set back or situated farther from the coastline, it must be capable of resisting high winds and other hazards that may occur at the site.
Using recommended building practices for constructing new homes in coastal area is important and may avoid many future problems. For example, building at a site away from eroding shorelines and high-hazard areas is advisable. Also, flat or low-sloped porch roofs, overhangs, and gable ends are subject to increases uplift in high winds. Buildings that are both tall and narrow are subject to overturning. Each of these problems may be avoided through the design process by making the building more resistant to high winds.
To qualify for flood insurance, the lowest floor must be elevated above the Design Flood Elevation (DFE), i.e., the bottom of the lowest horizontal structural member supporting the lowest floor must be above the DFE. Also, an open foundation is required in certain flood hazard zones, i.e., VE zones, and may not be obstructed below the elevated portion of the building. Further the foundation must be deep enough to resist the effects of scour and erosion, i.e., strong enough to resist wave, current, flood, and debris forces and capable of transferring wind and seismic forces on upper stories to the ground.
Additionally, the connection of the walls and floor to the foundation must be sound and any building materials below the DFE should be flood-resistant materials. All exposed materials should be moisture-resistant and decay-resistant and any metals should have enhanced corrosion protection.
These and other recommended building practices are advisable for new building construction in coastal areas. Needless to say, for existing homes and other buildings in coastal areas, the new FEMA/NFIP requirements present difficult and serious problems. Existing homes may be rendered uninhabitable and/or ineligible for flood insurance. On the other hand, flood insurance premiums may be reduced by up to 60% by exceeding minimum siting, design, and construction practices.
As noted above, hundreds of thousands of existing buildings must be lifted and placed unto elevated foundations that comply with the requirements to qualify for flood insurance. The challenges to placing an existing structure (residential home or business building) onto requirement-compliant foundation include constructing the foundation underneath the lifted structure where there may be low ceiling tolerance, load testing one or more of the pipe piles of the foundation, and securing the foundation to the lifted structure.
Accordingly, a need exists for a new system and method for time- and cost-effectively lifting and securing existing homes and other buildings onto foundations that are requirement compliant and may withstand flood conditions better than traditional timber, helical or block foundations. Such systems and methods are disclosed herein.